Devices have been provided in combustion engines serving, for example, as power plants of aircraft, in order to maintain supply of lubricant to the engine when the attitude of the aircraft varies, and especially in upside-down attitudes.
There is a known system of maintaining dependable lubricant supply in which a plurality of oil pumps are arranged in the engine, with the oil to be delivered by that pump whose point of intake is immersed in the oil supply, being according to the tilt of the engine. This pump must then first deliver the oil to a reservoir to which another oil pump is connected, which finally delivers the oil to the lubricating circuit of the engine. In this known arrangement, however, the multiplicity of oil pumps required entails added cost. Besides, much space is required to accomodate the pumps, and the system is costly and trouble-prone owing to its complicated structure.
There is another known system in which at least one pivoted pendulum member in at least one special housing is provided, having a point of intake that will be immersed in the oil by gravity in every attitude of the engine to thus maintain the lubricant supply. While this arrangement requires only one oil pump, the rigging of the pendulum member likewise calls for a comparatively large structural and spatialoutlay, involving added cost. The systems mentioned moreover require additional precautions to prevent aspiration of air into the oil line.
Apart from these various systems, however, it is found in practice that the lubricating oil present in aviation combustion engines is always acted upon centrifugal force in most unusual flight attitudes, with the exception of the upside-down attitude; even, that is in steep banks and oblique attitudes as well as in helical maneuvers. This means that the oil supply, ordinarily contained in a lower storage tank is subject to such minor fluctuations that the lubricant supply to such an engine is safely maintained in the said flight attitude. The gravitational force acting on the lubricant is not much modified unless the engine remains in upside-down position with sustained deceleration, as is possible in stunt flying for example. For such a rare and extreme case, the known devices are too elaborate and costly in design.